This invention relates to adhesive systems used in the manufacture of certain lignocellulosic products, and to the lignocellulosic products which are formed using these adhesive systems. More specifically, this invention is directed to adhesive systems comprising aldehyde resins used in the manufacture of certain lignocelluosic products, and to the lignocellulosic products which are formed using these aldehyde resin adhesive systems.
Aldehyde resin adhesive systems are well known in the manufacture of various lignocellulosic products. In order to improve the cost of manufacturing these lignocellulosic products, certain materials known as extenders and fillers can be added to these adhesive systems. Extenders are typically substances which are added to an adhesive to reduce the amount of the primary binder required per unit area, and in turn increasing the profitability of selling the resultant lignocellulosic product. Extenders are generally designed so that they do not have an adverse effect on the binding action of the adhesive system, and preferably have a positive effect on the binding properties of the adhesive system. Examples of extenders used in aldehyde resin adhesive systems are organic flours, typically ground vegetable flour or grain flour, such as for example, corn flour or wheat flour.
A filler is a relatively non-adhesive substance added to an adhesive to improve it's working properties. For example, fillers are used to fill and bridge holes and irregularities in the outer surfaces of lignocellulosic materials. Common fillers include ground alder bark, ground nut shell flour, and furfural residue from corn cob (FRC).
A problem which can exist with respect to the use of extenders and/or fillers is that they can have an undesirable effect on the chemical and/or the physical properties of the aldehyde resin adhesive systems to which they are added. This can impede the performance of the modified aldehyde resin adhesive systems during subsequent use in product manufacture.